One of North America’s premier rotary screw compressor manufacturers has ordered a new, ultra-precise TG 350E CNC rotor grinding machine from UK-based PTG Holroyd. The machine will be used alongside a previous generation TG 350 model that has been in reliable daily operation at the compressor rotor manufacturing facility since 2008.

Valued in excess of $1.7 million, the new TG 350E rotor grinder is currently in build at PTG Holroyd’s Rochdale technology centre and is scheduled to ship in springtime 2023. It will be used by the customer to precision-grind screw rotors of up to 350 mm in diameter and 1800 mm in length and will bring even higher levels of flexibility to the company’s manufacturing strategies.

“Around the globe, PTG Holroyd’s rotor milling, rotor grinding and gear grinding machines are renowned for their accuracy, reliability and longevity,” comments PTG Holroyd Sales Director, Mark Curran. “Offering the most up-to-date control technologies,” he continues, “new TG Series models further build on the uncompromising capabilities that have helped established PTG Holroyd rotor grinding machines as a favoured choice for many manufacturers of refrigeration compressors, helical rotors and threads. Although we are not able to name this North American customer, it is nonetheless rewarding to know that the positive experience gained by using one of our machines over so many years, played a significant part in their decision to order a second PTG Holroyd machine.”

High speed and high accuracy

PTG Holroyd TG Series machines are widely recognised as providing the industry benchmark for high speed, high accuracy, efficient stock removal. Advanced automation means reduced setup time, while a significant amount of production time can be saved due to the fact that each machine’s diamond dressing discs are continuously dressed during the semi-finish grinding cycles. The TG range starts with the TG 50E, a machine designed to precision grind components of up to 50 mm in diameter and 610 mm in length, with models offering stepped increases in capability up to the production of helical components measuring 450 mm in diameter and 2020 mm in length.

Equally suited to prototyping, batch and volume production, TG Series machines are designed primarily for the finish grinding of helical screw components such as worm screws and rotors after they have been milled to a rough or semi-finished state. TG models offer production rates and accuracies to suit precise manufacturing strategies. Fully automated on-machine probing provides closed loop feedback of corrections to the dresser wheel and does not require a high level of operator skill.

TG Series rotor grinding machines, at-a-glance:

• High levels of accuracy and efficient stock removal
• Developed for prototyping, batch and volume production
• Accelerated and simplified setup
• Fully automated grinding wheel balancing system
• Powerful, intuitive touch screen programming
• Unique on-board Holroyd 3D CMM component scanning probe with fully automatic compensation feedback
• High-power, high-speed grinding spindles
• Optional hollow spindle for longer components
• Advanced, in-process wheel dressing system
• Large diameter grinding wheels for maximum wheel life
• Optional Holroyd Profile Management System (HPMS)
• Component diameters from 0 mm to 450 mm depending on component and profile
• Maximum component weight: 700 kg